john harwood is in kentucky with the preview. john. >> reporter: michelle, this is going to be a fascinating night between two number twos who might, in the future, be number ones. for right now, they're trying to help their tickets. joe biden, as you mentioned, who arrived in danville. he's now chilling at a supporter's house with his family before going to the debate tonight, has got a lot on the line because democrats were feeling let down by president obama's performance last week. what joe biden has to do is to buck up those democrats, show he's going to be aggressive in going after the republican ticket, and, you know, he has experience in the venue. he debated sarah palin four years ago, although much different then. that was a comparatively genial event. i would expect him to be quite aggressive. from paul ryan's point of view, he's younger, so less experienced, but he's very fluent and skilled on policy. he came across very well in his republican convention speech. so i'd expect him to hold his own. for both side, dan qu